Pure fluid addition and subtraction

ABSTRACT

Accurate analog addition and subtraction are performed in a proportional fluidic amplifier of the stream interaction type in which a pair of control nozzles are superposed, one atop the other, so as to issue their respective control streams against the same point in the power stream flow path.

United States Patent 3,238,961 3/1966 l-latch,Jr. ung 131 .5

UNITED STATES PATENTS Di Camillo 1451 June 6, 1972 541 PURE FLUID ADDITION AND 3,272,214 9/1966 Warren ..137/8 1.5 SUBT C N 3,285,264 11/1966 Boothe ...l37/81 5 0 3,457,935 7/1969 Kantola ...l37/81.5 [72] Inventor: CarmineV. Di Camillo, Silver Spring, Md. 3,460,556 8/1969 Sowers ..l37/81.5

1[73] Assignee: Bowles Fluidics Corporation 1 Primary Ex amt-n er samu 61 Scott 22 Filed: Feb. 18, 1969 Attorney-Rose &

[21] Appl. No.: 800,163 [57] ABSTRACT I I Accurate analog addition and subtraction are performed in a [52] U.S. CL; .....l37/8l.5 proportional fluidic amplifier of the stream interaction type in [5 1] Int. Cl. ...F15c 1/14 which a pair of control nozzles are superposed, one atop the [58] Field of Search ..l37/8l.5 other, so as to issue their respective control streams against 9 the same point in the power stream flow path. [56] References Cited m Pr zv vs PURE FLUID ADDITION AND SUB'I'RACIION BACKGROUND OF THE INVENTION plifiers. More specifically, if two pressure signals are to be added they must produce a net power stream deflection which is proportional to the sum of the signal pressures. This requires that ,both signalsbe applied against the same power stream location; this is true because if one control signal issues upstream of the other, the former has a greater effect than the latter in deflecting the power stream. In prior art amplifiers, control streams representing input signals are issued co-planar with one another and the power stream and thus of necessity must act against different downstream locations of the power stream.

i The above problem exists even in those prior art fluidic amplifiers in which control passages are joined to issue multiple control signals from one nozzle. In this regard, the multiple sigrials, though issuing from a common nozzle, still issue from different downstream locations of that nozzle and hence have different effects on power streamdeflection. Moreover, there is significant'interaction between the control signals in this configuration and this causes inaccuracies in signal addition as monitored by power stream deflection.

It is an object of the present invention to provide a fluidic amplifier of the stream interaction type capable of accurately adding two input pressure signals.

' It is another object of the present invention to provide a fluidic element of the stream interaction type in which power stream deflection serves as an accurate indication of the sum SUMMARY OF THE INVENTION The invention comprises superposing two control nozzles, one atop the other, so that control streams issued therefrom operate against respective halves, of the power stream at the same location in the. power stream flow path. In one embodimerit, the amplifier is fabricated from two cover plates, each having half of the amplifier configuration formed in one face. The twoplates are joined, face-to-face, with a barrier plate disposed between the cover plates in the region of the control nozzles. Each control noule is then divided into two superposed control nozzles arranged to effect power stream displacement from the same point in the power stream flow path.

BRIEF DESCRIPTION OF THE DRAWINGS The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific surfaces of each of flat plates 11 and 13. Plates 11 and 13 are sealed together, face-to-face, in fluidtight relationship by machine screws, clamps, adhesives or other suitable manner. For the sake of facilitating the understanding of the present invention, plates 11 and 13 are illustrated as being composed of clear plastic; however, it should be understood that any material compatible with the working fluid may be used in the construction of amplifier 10.

The amplifier comprises a power. nozzle 15 adapted to receive pressurized fluid and respond thereto by issuing a power stream of the fluid into an interaction region 17. Left and right sidewalls 19, 21 of region 17 are set back sufiiciently to prevent the power stream from locking on to either sidewall due to boundary layer phenomena. Vent holes 23 and 25 are bored completely through either one or both of plates 11 and 13 to provide fluid communication between ambient pressure and the interaction region 17. 7

Left and right outlet passages 27 and 29 respectively are disposed at the downstream end of interaction region 17 in receiving relation with the power stream. Outlet passages 27 and 29 are positioned symmetrically with respect to the longitudinal axis of power nozzle 15; however, this is a matter of design choice and not limiting on the scope of the invention.

Amplifier 10 is provided with a pair of right control nozzles A and B superposed on one another with nozzle A atop nozzle B as viewed in FIG. 1. Formation of nozzles A and B is accomplished in much the same manner as the other passages and nozzles in amplifier 10; that is, nozzle A, is formed in plate 11 and nozzle-B in plate 13. Simple joinder of plates 11 and 13 would thus provide a single right control nozzle; however, a thin barrier plate 31 is inserted between plates 11 and 13 in the region of the right control nozzle so that two distinct suillustrated, barrier plate 31 may be sufiiciently thin as to not embodiment thereof, especially when taken in conjunction DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring specifically to FIGS. land 2 of the accompanying drawing, there is illustrated a proportional fluidic amplifier 10 of the stream interaction type. The cavities, passages and nozzles required to provide amplifier 10 are formed in respective require such depressions in plates 11 and 13. In either case, the barrier plate permits independent pressure signals to be applied to control nozzles A and B and to remain isolated until issued as control streams into interaction region 17.

In like manner left control nozzles C and D are provided, separated by a barrier plate 33, wherein nozzle C is superposed above nozzle D as viewed in FIG. 1.

The effect of the superposed control nozzles is to permit two independent pressure signals to operate at the same point in the power stream flow path. This is illustrated schematically in FIG. 3 wherein signals applied to right control nozzles A and B are shown to act at the same point and signals applied to left control nozzles C and D are shown to act at the same point. In the symmetrical configuration illustrated, nozzle pair A and B act on the power stream in a manner exactly opposite to that in which nozzle pair C and D act.

In actuality, the control stream issued from control nozzle A may be considered as acting on the top half of the power stream in the vicinity of the control nozzle outlet opening. Likewise, the control stream issued from control nozzle B may be considered as acting on the bottom half of the power stream in this vicinity. The overall effect is to permit issuance of two control streams having like efiectiveness as regards powerstream deflection.

Addition, as comprehended by the present invention, is monitored in terms of power stream deflection. Power stream deflection, in turn, is measured as a function of the differential pressure, APO, appearing across outlet passages 27 and 29. Thus, if we assume that two pressure signals to be added are applied to control nozzles A and B, the differential pressure appearing across passages 27 and 29 is proportional to the sum of the input signal pressures. Likewise, the differential pressure of opposite sense, that is, appearing across passages 29 and 27, is proportional to the sum of the input signal pressures at control nozzles C and D.

The two plate (11 and 12) configuration of amplifier is possibly the most simply constmcted embodiment of the present invention, but clearly not the only possible construction. The barrier plates may, for example, be constructed integrally with the plate or plates in which the amplifier passages are formed. For example, in the three-layer fluidic amplifier construction exemplified by US. Pat. No. 3,122,165, the barrier plates may be part of the center layer. Additionally, where a single cover plate is employed to seal the passages formed in a further plate (as described in U.S. Pat. No. 3,275,013) the barrier plates may either be inserts adapted to fit in the control passages of the latter plate or alternatively may be formed as part of the latter plate.

The present invention has also been found to provide excellent results in performing analog subtraction operations on input pressure signals. In particular, it was found that excellent analog subtraction was achieved by applying the two input signals to control ports A and D respectively or to control ports B and C respectively. As described above in relation to the addition operation, subtraction is monitored in terms of power stream deflection produced by the difference between the input signal pressures. The differential pressure APo appearing across outlet passages 27 and 29 serves as a measure of power stream deflection.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described'may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

I claim:

1. A fluidic amplifier of the stream interaction type comprising:

an interaction region;

a power nozzle responsive to application of pressurized fluid thereto for issuing a power stream of fluid into said interaction region;

means constraining said power stream to flow in a predetermined plane;

at least one outlet passage disposed for receiving portions of said power stream as a function of power stream deflection; and

at least first and second control nozzles superposed one atop the other and disposed to respond to application of respective fluid signals thereto for issuing respective control streams into said interaction region and into deflecting relationship with said power stream at the same point in the power stream flow path.

2. The fluidic amplifier according to claim 1 wherein said amplifier is of the proportional type and is constructed from two plates, each plate having a flat surface into which the configuration of said amplifier is cut, the plates being joined faceto-face in fluidtight relationship with the respective amplifier configurations in precise registration, and wherein said superposed first and second control nozzles are formed by a barrier plate interposed between said two plates in the region of said control nozzles.

3. The fluidic amplifier according to claim 1 further comprising a second outlet passage disposed to receive a portion of fluid from said power stream as a function of power stream deflection, said first and second outlet passages being disposed to provide a differential output pressure as a function of power stream deflection.

4. The fluidic amplifier according to claim 3 further comprising third and fourth control nozzles superposed one atop the other and disposed to respond to application of respective fluid signals thereto for issuing respective control stream into deflecting relationship with said power stream at the same point in the power stream flow path, said third and fourth control nozzles being further disposed to issue their respective control stream in substantial opposition to the control stream issued by said first and second control noules.

5. The fluidic'amplifier according to claim 4 wherein said am6plifier is of the pro rtional tygii.

. The fluidic amp ifier accor g to claim 5 wherein said amplifier is constructed from two plates, each plate having the various passages, interaction region and nozzle configurations of the amplifier cut into a respective face thereof, the two plates being joined face-to-face in fluidtight relationship with the amplifier configuration of both plates in precise registration and wherein first and second barrier plates are disposed between the plates in the region of said control nozzles so that each of said first, second, third and fourth control nozzles is defined between a cut-out portion of a respective plate and a respective one of the barrier plates.

7. An analog fluidic amplifier of the stream interaction type comprising:

an interaction region;

power nome means responsive to application of pressurized fluid thereto for issuing a power stream of fluid into said interaction region;

means constraining said power stream for flow in a single plane through said interaction region;

a pair of outlet passages in said single plane disposed for receiving portions of said power stream from said interaction region as a function of power stream deflection in said interaction region; and

first and second control nozzles superposed one on the other and arranged to issue control fluid applied thereto into impingement against said power stream in said interaction region at locations which are equidistant from said power nozzle means. 

1. A fluidic amplifier of the stream interaction type comprising: an interaction region; a power nozzle responsive to application of pressurized fluid thereto for issuing a power stream of fluid into said interaction region; means constraining said power stream to flow in a predetermined plane; at least one outlet passage disposed for receiving portions of said power stream as a function of power stream deflection; and at least first and second control nozzles superposed one atop the other and disposed to respond to application of respective fluid signals thereto for issuing respective control streams into said interaction region and into deflecting relationship with said power stream at the same point in the power stream flow path.
 2. The fluidic amplifier according to claim 1 wherein said amplifier is of the proportional type and is constructed from two plates, each plate having a flat surface into which the configuration of said amplifier is cut, the plates being joined face-to-face in fluidtight relationship with the respective amplifier configurations in precise registration, and wherein said superposed first and second control nozzles are formed by a barrier plate interposed between said two plates in the region of said control Nozzles.
 3. The fluidic amplifier according to claim 1 further comprising a second outlet passage disposed to receive a portion of fluid from said power stream as a function of power stream deflection, said first and second outlet passages being disposed to provide a differential output pressure as a function of power stream deflection.
 4. The fluidic amplifier according to claim 3 further comprising third and fourth control nozzles superposed one atop the other and disposed to respond to application of respective fluid signals thereto for issuing respective control stream into deflecting relationship with said power stream at the same point in the power stream flow path, said third and fourth control nozzles being further disposed to issue their respective control stream in substantial opposition to the control stream issued by said first and second control nozzles.
 5. The fluidic amplifier according to claim 4 wherein said amplifier is of the proportional type.
 6. The fluidic amplifier according to claim 5 wherein said amplifier is constructed from two plates, each plate having the various passages, interaction region and nozzle configurations of the amplifier cut into a respective face thereof, the two plates being joined face-to-face in fluidtight relationship with the amplifier configuration of both plates in precise registration and wherein first and second barrier plates are disposed between the plates in the region of said control nozzles so that each of said first, second, third and fourth control nozzles is defined between a cut-out portion of a respective plate and a respective one of the barrier plates.
 7. An analog fluidic amplifier of the stream interaction type comprising: an interaction region; power nozzle means responsive to application of pressurized fluid thereto for issuing a power stream of fluid into said interaction region; means constraining said power stream for flow in a single plane through said interaction region; a pair of outlet passages in said single plane disposed for receiving portions of said power stream from said interaction region as a function of power stream deflection in said interaction region; and first and second control nozzles superposed one on the other and arranged to issue control fluid applied thereto into impingement against said power stream in said interaction region at locations which are equidistant from said power nozzle means. 